Reclaiming rubber.



be a

ORRIN A.'WHEELER, OF CHICAGO, ILLINOIS, ASSIG-NOR 0F ONE-THIRD TO EDWARDD. LOEWENTHAL AND ONE-THIRD TO B. LCEWENTHAL, BOTH OF CHICAGO, ILLINOIS.

RECLAIMING RUBBER.

Be it known that I, ORRIN A. WHEELER, a resident of Chicago, in thecounty of Cook and State of Illinois, have invented certain new anduseful Improvements in Reclaiming Rubber, of which the following is afull, clear, and exact description.

The invention relates to the art of reclaiming rubber scrap containingcotton fiber.

The object of the invention is to recover and utilize the fibercontained in the waste vulcanized rubber, such as shoes, vehicletires,hose, etc, by treating the'scra-p so that the cellulose of the fiber maybe left in the reclaimed product and utilized instead of being removedtherefrom.

Through experiments, I have discovered that the cotton fiber invulcanized rubber scrap can be converted into atenacious cellulose whichis insoluble in water and struc- I tureless, previous to 01' during thetime of,

devulcanization of the scrap without separation of the rubber from thefiber; and that when tenacious cellulose and the devulcanized rubber arecombined and sulfur in various proportions is added, the resultantproduct will have qualities superior, for many purposes, to new rubberor new rubber products, because the tenacious, elastic cellulose rendersthe product durable, stable, lessens "its weight as compared with newrubber, and lessens the cost of production of reclaimed materials. Hardrubber made from reclaimed scrap containing fiber will endure a muchhigher degree of heat than ordinary rubber and will better resist theaction of oils, acids, alkalis than ordinary hard rubber and can bemanufactured at a materially less cost than hard rubber made in theusual way, because all of the waste fiber is utilized to improve thematerial.

The improved method of treating rubber scrap, containing fiber is asfollows: The scrap, such as tires, shoes, hose, etc., is ground andpulverized in the usual manner. The pulverized material is then treatedwith a strong solution (about 20%) of caustic soda and allowed to standin a cool place approximately from three to five hours. Next thematerial is placed in a digester which is equipped so that it can beScaled or closed up tightly and carbon disulfid (CS about one pound moreor less according to the character of the Specification of LettersPatent.

I sealed.

rateateaa aia, was.

No Drawing. Application filed October 30, 1912. Serial No. 728,633.

' To all whom it may concern i material treated to about ten pounds ofdry rubber scrap is added to material, and then the digester is closedand hermetically This mixture is permitted to remain in the digesterfrom one to five hours, to permit chemical reaction to occur, thedigester being operated during such a period to stir and agitate themass to facilitate said reaction and thereby bring about acombination-of the soda and sulfur with the cellulose and so producing acellulose Xanthogenate. On completion of this reaction, the rubber andfiber is converted into a sticky cohesive mass. Next, Water in quantityapproximately equal to the original dry rubberis added to the materialin the digester and the agitation is continued, the water mixing withthe cellulose to distend it. Next the mass in the digester is heated bycarefully raising the stean1-1: ressure in the heating-chamber aroundthe digester, to approximately one hundred pounds, which pressure iskept up for a period ranging approximately from 15 to 20 hours,according to the stock under treatment and during such time, agitationandstirring. of the mass will be continued part of or all of the time.This heating causes the cellulose to become insoluble in water anddevulcanizes the rubber in the presence of caustic soda and carbondisulfid. In this process, carbon disulfid tends to dissolve thecombined sulfur and dissolves all the free sulfur, and when heated,produces a high pressure in the digester thereby causing thoroughimpregnation of every particle of rubber under treatment and greatlyassisting in the recovery of the rubber. The solvent may, of course,

be recovered.

I In this method of reclaiming rubber, the cotton fiber, that is usuallydestroyed or removed in other processes, is permittedto remain with therubber and utilized, and becomes a valuableingredient in both soft andhard rubber compounds. The rubber and clastictenacious cellulose uniteand intermingle so that an article made therefrom will possess thetoughness and wearing qualities of new and pure rubber and will besuperior for some purposes,particularly Where thearticle made from thereclaimed product is to be subjected to heat, is ,exposed to theelements,,or to the action of oils, acids and alkalis. Since thecellulose of the fibrous material in the scrap is utilized to advantagein the product, thecost is less than under any previous process in whichthe fiber is destroyed and removed or removed without being destroyed.

An excellent grade of material'can be made from the product of theprocess with the addition of sulfur, and with the addition of some ofthe cheaper gums such as pontianiac, acra flake, guayule, an articleof ahigher grade can be produced at a low cost. If desired, new rubber maybe added. A comparatively good grade of reclaimed rubber can be obtainedby introducing the alkali and carbon disulfid at the same time butbetter results are believed to result from the successive treatment withthe alkaliand carbon disulfid, as hereinbefore set forth.

The invention is not to be understood as restricted to the reciseprocess and proportions set forth since these may be modified by thoseskilled in the art without depart;- ing from the spiritandscope of theinvention.

Having thus described the invention, what I claim as new and desire tosecure by Letters Patent, is:

.1. That improvement in reclaiming vulcanized rubber scrap containingcellulose, which consists in subjecting it to the action of an alkalisolution and carbon disulfid.

2. That improvement in reclaiming vulcanized rubber scrap containingcellulose, which consists in'first treating the scrap with an alkalisolution and then with carbon disulfid in a, closed receptacle.

3. That improvement in reclaiming vulcanized rubber scrap containingcellulose, which consists in first treating the scrap with an alkalisolution, then with carbon disulfid in a closed receptacle, then addingwater to the mass, and then heating the same.

-l That improvement in reclaiming vulcanized rubber scrap containingcellulose, which consists, in pulverizing the scrap, treating it with asolution of alkali at nor mal temperature for approximately an hour ormore, then adding. carbon disulfid, then permitting chemical reaction tooccur,'and then heating the mass. v

5. That improvement in reclaiming vulcanized rubber scrap containingcellulose, which consists in treating pulverized scrap with an alkalisolution and carbon disulfid in the presence of heat.

6. That improvement in reclaiming vulcanized rubber scrap containingcellulose,

which consists in first treating the scrap with an alkali solution for aperiod, then treating it with carbon disulfid for a sufiicient period topermit chemical reaction to occur tox-convert the rubber and fiber intoa cohesive mass and thereafter subjecting the mass to heat.

7. That improvement in reclaiming rubber scrap containing cellulosefiber which consists in treating such scrap with a sulfur compound andasuitable compound of an alakli metal until the cellulose is convertedinto a cellulose Xanthogenate.

8. That improvement in reclaiming rubber scrap containing cellulosefiber which consists in treating said scrap with a compound of sulfurand a suitable compound of an alkali metal to convert the cellulose intoa cellulose xanthogenate and devulcanizing the rubber by means ofthevsaid compound of sulfur and compound of an alkali metal and heat.

9. The process of reclaiming rubber which consists in subjecting amixture of vulcanized rubber and cellulose fiber, to treatment with asulfur compound and an alkali under heat and pressure.

10. The process of reclaiming rubber which consists in subjectingvulcanized rubber containing cellulose fiber to treatment with carbondisulfid and caustic soda until devulcanization of the rubber iseffected, and a cellulose Xanthogena-te produced.

11. The process of reclaiming rubber which consists in treating the rawmaterial with a solution of caustic alkali, allowing the mass so treatedto stand, then placing it in a digester, adding carbon disulfid, andstirring, then adding water and stirring, and then subjecting the massto heat.

12. The process of reclaiming rubber which consists in treatingpulverized scrap rubber with a strong solution of caustic soda, allowingthe material so treated to stand for from three to live hours, placingit in a digester, adding carbon disulfid, agitating for from one to fivehours, adding water in quantity equal to the rubber present, andsubjecting to heat whereby the cellulose present in the scrap isconverted into an insoluble and flexible compound of sulfur andcellulose intimately intermingled with devulcanized rubber.

ORRIN A. WHEELER. Witnesses Fnnn GERLACH,

MILDRED A. STUMPF.

